1) Field of the Invention
The present invention relates to a delivery device and, in more particular, to a delivery device that is capable of being positioned within a lumen and viewing the lumen through a window.
2) Description of Related Art
Stents are devices that are inserted into body lumina such as vessels or passages to keep the lumen open and prevent closure due to a stricture, external compression, or internal obstruction. In particular, stents are commonly used to keep blood vessels open in the coronary arteries, and they are frequently inserted into the ureters to maintain drainage from the kidneys, the bile duct for pancreatic cancer or cholangiocarcinoma, or the esophagus or airways for strictures or cancer. Vascular as well as nonvascular stenting has evolved significantly; unfortunately, there remain significant limitations with respect to effectively implanting the stents into a patient's lumen.
In order to serve its desired function, the stent must be delivered precisely and oriented correctly. Improper installation can lead to tissue luminal inflammation and tissue granulation. In order to facilitate the delivery of stents, delivery devices, such as endoscopes and catheters, have been utilized to deploy stents more precisely. Unfortunately, guidance of the stent has substantially remained a function of physician skill resulting from substantial practice. This fact has become particularly evident with the advent of radially expanding stents. The physician frequently needs to measure the length of the lesion, align a distal end of the of the delivery device, and rely on accurate deployment to ensure that the entire lesion is covered by the stent. Moreover, delivery devices typically do not give physicians adequate visual certainty that the device has been installed at the desired target site. Optical devices are typically employed at a distal end of the delivery device, which provides limited visibility of the entire lesion with respect to the stent. If after full deployment of the stent, the physician discovers the stent has been implanted incorrectly, there is no conventional way of correcting the error short of removing the stent.
Techniques have been developed to address the problem of increasing visibility of the lesion prior to deploying the stent. For example, U.S. Patent Application Publication No. 20040193243 to Mangiardi et al. which is assigned to the present assignee and incorporated herein by reference, discloses a medical appliance optical delivery and deployment apparatus. The apparatus includes an inner tubular member disposed within an outer tubular member, where the outer tubular member is typically shorter than the inner tubular member and movable relative to the inner tubular member. A distal region of the outer tubular member surrounds the stent and maintains the stent in a crimped delivery configuration, while a distal region of the inner tubular member is surrounded by the stent. The outer tubular member may be clear so that the inner tubular member and markers are visible therethrough. An optical guidewire may extend through the inner tubular member or utility channels defined in the outer tubular member to a distal tip, or the distal tip may be configured to have a light source and lens. In addition, the inner tubular member may include optical windows proximate to the distal tip and are preferably beveled and oval to facilitate viewing with an optical instrument. The optical windows may also be staggered along the inner tubular member to increase visualization proximate to the distal tip. Once properly positioned at a site of a lesion, the outer tubular member is retracted to deploy the stent and allow the stent to radially expand.
The inner and outer tubular members, optical instruments, and optical windows provide increased visualization of the lesion prior to deploying the stent. Despite these improvements, additional innovations in positioning an implantable device and visualizing a lesion to promote more accurate delivery of the implantable device are also desired.
Therefore, there is a need in the industry for a delivery device that is capable of effectively and accurately positioning an implantable device within a patient's lumen. In addition, there is a need for a delivery device that is capable of increasing the visibility of the lumen prior to deploying the implantable device.